Absorption glass and method of making it



' Patented Mays, 1925.

UNITED STATES,

PATENT orr ce.

JOSEPH CARL PARKINSON', OF 'l'ARENTUM, PEIN'NSYLV'ANTLA; ASSIGNOB TPITTS- BURGH PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

ABSORPTION GLASS AND HET HOD 0F KAKING i m mam g.

-To allwhom it may concern:

Be it known that I, JOSEPH Cam, PARKIN- soN, a citizen of the UnitedStates, and a resident of Tarentiim, in the county of Alle- '10 Theinvention relates to glass for absorbing the ultra violet rays of lightand has for its principal object the production of an improved glass ofthis type which req uires a, relative less as op have heretofore beenproduced having the propert of'high ultra violet ray absorption. lass ofthis character is desirable .20 for use in Windshields and other forumwhere a tinted-glass is objectionable and also in some cases inspectacle glass.

One of the compounds most commonly used heretofore in producing .thetinted absorption glass is cerium oxid (-CeO,)' which has beenintroduced into the batch in the form of a nitrate, carbonate or hydrateor other salt. In any of its commercial forms this compound always givesa tinted glass having a pink tinge when the glass is viewed ed ewise inconnection with artificial light. T llS color characteristic isapparently due to the presence with the cerium-oxid of small percentagesof other oxids, 85 particularly didymium an agency employed in finingthe lass. I 5 have found t at when" technical y pure cerium oxid, saltor other compound containing cerium practically free from didym- 40 iumis employed in a reducing batch the desired result is achieved, namely,a clear, colorless glass having-the required absorption properties. Byreducing batch is meant one of the type employing reducing compoundssuch as'coal, charcoal, arsenic, etc., commqnly used for that purpose.This type' of batch is distinct from what may be termed an oxidizingbatch, in which compounds such.as nitrates are used for mainmining anoxidizing condition during melty small amount 0t expen- 15 em; chemicalsand which is clear and colorto the tinted glasses whichis also due tothe Application filed November is, .1922. Serial imam-,1;

The following batch formula is typical of what may be used to produce asatisfac tory glass: f 1

Pounds.

Sand a- 1,000 Soda ash 423 I Whiting 100 Cerium yd a Salt 25 eu- Arsenicor antimony 5 7 i. Salt cake-.. f? Coal' 3 tech 'cally pure and thepercentage-oi d1- '1 dymium oxid'in this compound is so small? that ithas no color-eifect, which is quite a difierent situationas comparedwith the or di nary commercial cerium compound which-52 may contain asmuch as 20% of didymium oxid.

The amount of cerium hydrate which ma be employed may be very largelyincrease over that specified above without giving any a color to theglass produced, but at the same time no perceptible improvement in ,theabsorption properties is involvedland the 8K- pense is increased asthehydrateir one of the most expensive ingredients in the batch. Inplace of the cerium hydrate other cerium 30 compounds may be employed,provided they contain arelativel low percenta e of (ii-- dymium and.provi ed adjustment made to secure the proper amount of cerium exidcorrespondin to that contained by the hydrate. 35 If, in pface ofthebatch employed, one-is used employing a nitrate in place of the saltcake, so that thefining reaction occurs.

from the nitrate in connection with arsenic or similar matei'iah atinted glass results even though a technically pure cerium compoundisemployed;

The lass produced by the improved process is ear and colorless and hashigh ultraviolet ra absorption qualities.

\Vhat claim is:

1. A. substantially clear, colorless glass with high ultra violet rayabsorbing properties containing cerium oxid and substantially free fromdidymium oxid and forum-i by fusing a substantially pure ceriumcompoundiu a,reducing batch.

The cerium hydrate which 'is'eznployed 2. The method of pmdning glass ofhigh ultra violet. ray absorbingpi'opvrtivs which rousisls "in fusing,'a' substantially pure cerium compound in a reducing batch. 5 3. Themethod of pi'oducing'glass of high ultraviolet ray ahs'm-bing propertieswhich consists in fusing a substantially pure.

voriuni compound in a reducing lmlvh in- "ulmling salt cake as alindin;agent.

bar, 1922.

' J. CARL IARKINSON.

